This invention relates to reinforced carbon and graphite articles and more particularly to reinforced carbon and graphite articles having improved physical properties and increased oxidation resistance at high temperatures as compared to conventional reinforced carbon and graphite articles.
Reinforced carbon and graphite articles have found many applications in modern industry, particularly in the aerospace and aviation field, where resistance to corrosion, high temperature, thermal shock and excellent wear characteristics are required of the material to be used. In this connection articles consisting essentially of carbon or graphite fibers bound by a carbon or graphite matrix into integral bodies have been found to be exceedingly useful. Highly satisfactory reinforced carbon and graphite articles and the method of producing them is disclosed by Rohl and Robinson in application Ser. No. 478,033 filed Aug. 5, 1965, now U.S. Pat. No. 3,462,289, entitled Process for Producing Reinforced Carbon and Graphite Bodies. Another method for producing laminated graphite articles is disclosed in U.S. pat. No. 3,174,895 to Gibson et al.
Reinforced carbon and graphite bodies are subject to delamination when placed under high stress. Furthermore, when subjected to high temperatures in the presence of oxygen the useful life of such bodies is shortened due to the oxidation of the carbon and graphite in the reinforcing fibers and in the binder.
Accordingly it is an object of this invention to provide a reinforced carbon or graphite article having improved oxidation resistance and increased strength characteristics as compared to conventional reinforced carbon and graphite articles.
It is another object of this invention to provide an improved reinforced carbon or graphite article having incorporated therein the in situ reaction product of carbon and a boron containing additive whereby the strength characteristics and oxidation resistance of the article are enhanced.
These and other objects and advantages of this invention will be apparent upon a consideration of the following description of the embodiments described below and the novel features thereof will be particularly pointed out hereinafter in connection with the appended claims.
In the course of the following description and in the claims appended hereto the composition of reinforced bodies made in accordance with the present invention will be referred to as being carbon. It will be noted, however, that by the use of the word carbon applicant intends to refer to carbon in all its forms, including graphite.